imaging exam 1 Flashcards
which types of imaging are non-ionizing?
ultrasound and MRI
which type of imaging is emission?
bone scan
on x-ray what is dark?
air, fat, water
on x-ray what is light?
metal, bone
position vs. projection
position: pt (recumbent vs. weight bearing)
projection: direction of beam
orthogonal imaging
2 images at least 90 degrees apart
radiograph search pattern
A: alignment
B: bone density
C: cartilage space
S: soft tissue
measuring units of CT
hounsfield unit
indications of CT
- hidden fracture
- high risk trauma
- loose bodies in joint
- degenerative changes in spine
contraindications of CT
- no absolute
- based on radiation
CT vs. MRI
- CT cheaper
- CT faster
- CT less expensive
- CT less claustrophobic
- MRI less radiation
MRI contraindications
- cardiac pacemakers
- orthopedic hardware
- iron in the pigments
- unknown safety for fetus
- any other ferrous implants
T1 vs. T2
T1: anatomy
T2: pathology, H2O, water
is MRI good at soft tissue or bone?
excellent for soft tissue, not good at bone
MRI search patterns
A – Alignment of anatomy
-Continuity of ligaments, nerves, and muscle
B – Bone signal
-Look for alteration in bone signal
C – Cartilage
-OCD deformities and articular cartilage alterations
D – eDema
-“Footprint for injury”
S – Soft Tissue and Synovial tissue
-Disorder of the synovium, fat pads, bursae, etc.
hyperechoic
bright white on US
hypoechoic
black on US
nuclear imaging (bone scan)
application of radioactive substances for the diagnosis and treatment of disease
what can detect Paget’s disease
bone scan
PET scan
used to detect metastasis or other metabolic processes
DEXA
measures bone density and body composition
fracture risk assessment tool (FRAX)
used for probability of hip fracture
who gets surgical neck fracture
older adults
who gets humeral head fractures
children
ACR guidelines
- Radiographs = Typically first image of choice
- MR = Neg radiographs and suspect soft tissue injury. Preferred for stress fractures
- CT = Used to best visual occult fracture and for surgical planning as well as soft tissue.
- US = superficial soft tissue diagnosis, especially to see dynamic subluxations.
- US Septc Arthritis = US Centesis.
X-ray views of shoulder
APER
APIR
Axillary
y view
MRI/CT shoulder views
axial
oblique sagittal
oblique coronal
who gets supracondylar fractures?
second most common fracture in children
who gets radial head fractures?
adults
who gets olecranon fractures?
people in MVA, trauma
who gets elbow dislocation?
adults get ulnar
children get radial
which salter Harris fracture is most common?
type 2 S: straight across A: above L: low T: through ER: crush/erasure